Hydrogen damage behaviour of X80 steel under high voltage direct current interference

In this paper, the hydrogen damage behaviour of X80 steel under HVDC interference was investigated at different sites and applying voltages. The effect of application of a sustained tensile load during the interference testing on the ductility of steel was also studied. It was found that the interference modestly but consistently reduced the elongation of the steel, with dimples still dominating on the fracture surfaces. Application of a sustained tensile load significantly reduced the ductility of the steel, resulting in cleavage fracture dominant on the fracture surfaces on these samples. It also clearly increased the yield strength of the steel. The test results were explained by hydrogen trapping at dislocations and their retardation effect on dislocation movement during the SSRT.